Merge pull request #18746 from lnicola/sync-from-rust

minor: Sync from downstream

7 files changed, 135 insertions, 57 deletions

diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 0a563b1df26..136002b8e15 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -15,7 +15,7 @@ use std::iter::{self, once};
 
 use itertools::Itertools;
 use rustc_abi::ExternAbi;
-use rustc_attr::{ConstStability, StabilityLevel, StableSince};
+use rustc_attr_parsing::{ConstStability, StabilityLevel, StableSince};
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
@@ -1626,10 +1626,7 @@ pub(crate) trait PrintWithSpace {
 
 impl PrintWithSpace for hir::Safety {
     fn print_with_space(&self) -> &str {
-        match self {
-            hir::Safety::Unsafe => "unsafe ",
-            hir::Safety::Safe => "",
-        }
+        self.prefix_str()
     }
 }
 
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index 90c49270566..aa8fdaaee4c 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -344,35 +344,48 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
 }
 
 /// Make headings links with anchor IDs and build up TOC.
-struct LinkReplacer<'a, I: Iterator<Item = Event<'a>>> {
-    inner: I,
+struct LinkReplacerInner<'a> {
     links: &'a [RenderedLink],
     shortcut_link: Option<&'a RenderedLink>,
 }
 
+struct LinkReplacer<'a, I: Iterator<Item = Event<'a>>> {
+    iter: I,
+    inner: LinkReplacerInner<'a>,
+}
+
 impl<'a, I: Iterator<Item = Event<'a>>> LinkReplacer<'a, I> {
     fn new(iter: I, links: &'a [RenderedLink]) -> Self {
-        LinkReplacer { inner: iter, links, shortcut_link: None }
+        LinkReplacer { iter, inner: { LinkReplacerInner { links, shortcut_link: None } } }
     }
 }
 
-impl<'a, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, I> {
-    type Item = Event<'a>;
+// FIXME: Once we have specialized trait impl (for `Iterator` impl on `LinkReplacer`),
+// we can remove this type and move back `LinkReplacerInner` fields into `LinkReplacer`.
+struct SpannedLinkReplacer<'a, I: Iterator<Item = SpannedEvent<'a>>> {
+    iter: I,
+    inner: LinkReplacerInner<'a>,
+}
 
-    fn next(&mut self) -> Option<Self::Item> {
-        let mut event = self.inner.next();
+impl<'a, I: Iterator<Item = SpannedEvent<'a>>> SpannedLinkReplacer<'a, I> {
+    fn new(iter: I, links: &'a [RenderedLink]) -> Self {
+        SpannedLinkReplacer { iter, inner: { LinkReplacerInner { links, shortcut_link: None } } }
+    }
+}
 
+impl<'a> LinkReplacerInner<'a> {
+    fn handle_event(&mut self, event: &mut Event<'a>) {
         // Replace intra-doc links and remove disambiguators from shortcut links (`[fn@f]`).
-        match &mut event {
+        match event {
             // This is a shortcut link that was resolved by the broken_link_callback: `[fn@f]`
             // Remove any disambiguator.
-            Some(Event::Start(Tag::Link {
+            Event::Start(Tag::Link {
                 // [fn@f] or [fn@f][]
                 link_type: LinkType::ShortcutUnknown | LinkType::CollapsedUnknown,
                 dest_url,
                 title,
                 ..
-            })) => {
+            }) => {
                 debug!("saw start of shortcut link to {dest_url} with title {title}");
                 // If this is a shortcut link, it was resolved by the broken_link_callback.
                 // So the URL will already be updated properly.
@@ -389,13 +402,13 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, I> {
                 }
             }
             // Now that we're done with the shortcut link, don't replace any more text.
-            Some(Event::End(TagEnd::Link)) if self.shortcut_link.is_some() => {
+            Event::End(TagEnd::Link) if self.shortcut_link.is_some() => {
                 debug!("saw end of shortcut link");
                 self.shortcut_link = None;
             }
             // Handle backticks in inline code blocks, but only if we're in the middle of a shortcut link.
             // [`fn@f`]
-            Some(Event::Code(text)) => {
+            Event::Code(text) => {
                 trace!("saw code {text}");
                 if let Some(link) = self.shortcut_link {
                     // NOTE: this only replaces if the code block is the *entire* text.
@@ -418,7 +431,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, I> {
             }
             // Replace plain text in links, but only in the middle of a shortcut link.
             // [fn@f]
-            Some(Event::Text(text)) => {
+            Event::Text(text) => {
                 trace!("saw text {text}");
                 if let Some(link) = self.shortcut_link {
                     // NOTE: same limitations as `Event::Code`
@@ -434,7 +447,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, I> {
             }
             // If this is a link, but not a shortcut link,
             // replace the URL, since the broken_link_callback was not called.
-            Some(Event::Start(Tag::Link { dest_url, title, .. })) => {
+            Event::Start(Tag::Link { dest_url, title, .. }) => {
                 if let Some(link) =
                     self.links.iter().find(|&link| *link.original_text == **dest_url)
                 {
@@ -447,12 +460,33 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, I> {
             // Anything else couldn't have been a valid Rust path, so no need to replace the text.
             _ => {}
         }
+    }
+}
+
+impl<'a, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, I> {
+    type Item = Event<'a>;
 
+    fn next(&mut self) -> Option<Self::Item> {
+        let mut event = self.iter.next();
+        if let Some(ref mut event) = event {
+            self.inner.handle_event(event);
+        }
         // Yield the modified event
         event
     }
 }
 
+impl<'a, I: Iterator<Item = SpannedEvent<'a>>> Iterator for SpannedLinkReplacer<'a, I> {
+    type Item = SpannedEvent<'a>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let Some((mut event, range)) = self.iter.next() else { return None };
+        self.inner.handle_event(&mut event);
+        // Yield the modified event
+        Some((event, range))
+    }
+}
+
 /// Wrap HTML tables into `<div>` to prevent having the doc blocks width being too big.
 struct TableWrapper<'a, I: Iterator<Item = Event<'a>>> {
     inner: I,
@@ -1339,9 +1373,9 @@ impl<'a> Markdown<'a> {
 
         ids.handle_footnotes(|ids, existing_footnotes| {
             let p = HeadingLinks::new(p, None, ids, heading_offset);
+            let p = SpannedLinkReplacer::new(p, links);
             let p = footnotes::Footnotes::new(p, existing_footnotes);
-            let p = LinkReplacer::new(p.map(|(ev, _)| ev), links);
-            let p = TableWrapper::new(p);
+            let p = TableWrapper::new(p.map(|(ev, _)| ev));
             CodeBlocks::new(p, codes, edition, playground)
         })
     }
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index e013829e5e0..dfdf2cd6ec3 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -44,14 +44,15 @@ use std::path::PathBuf;
 use std::{fs, str};
 
 use rinja::Template;
-use rustc_attr::{ConstStability, DeprecatedSince, Deprecation, StabilityLevel, StableSince};
+use rustc_attr_parsing::{
+    ConstStability, DeprecatedSince, Deprecation, RustcVersion, StabilityLevel, StableSince,
+};
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_hir::Mutability;
 use rustc_hir::def_id::{DefId, DefIdSet};
 use rustc_middle::ty::print::PrintTraitRefExt;
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_session::RustcVersion;
 use rustc_span::symbol::{Symbol, sym};
 use rustc_span::{BytePos, DUMMY_SP, FileName, RealFileName};
 use serde::ser::SerializeMap;
@@ -835,12 +836,23 @@ fn assoc_href_attr(it: &clean::Item, link: AssocItemLink<'_>, cx: &Context<'_>)
     href.map(|href| format!(" href=\"{href}\"")).unwrap_or_default()
 }
 
+#[derive(Debug)]
+enum AssocConstValue<'a> {
+    // In trait definitions, it is relevant for the public API whether an
+    // associated constant comes with a default value, so even if we cannot
+    // render its value, the presence of a value must be shown using `= _`.
+    TraitDefault(&'a clean::ConstantKind),
+    // In impls, there is no need to show `= _`.
+    Impl(&'a clean::ConstantKind),
+    None,
+}
+
 fn assoc_const(
     w: &mut Buffer,
     it: &clean::Item,
     generics: &clean::Generics,
     ty: &clean::Type,
-    default: Option<&clean::ConstantKind>,
+    value: AssocConstValue<'_>,
     link: AssocItemLink<'_>,
     indent: usize,
     cx: &Context<'_>,
@@ -856,15 +868,20 @@ fn assoc_const(
         generics = generics.print(cx),
         ty = ty.print(cx),
     );
-    if let Some(default) = default {
-        w.write_str(" = ");
-
+    if let AssocConstValue::TraitDefault(konst) | AssocConstValue::Impl(konst) = value {
         // FIXME: `.value()` uses `clean::utils::format_integer_with_underscore_sep` under the
         //        hood which adds noisy underscores and a type suffix to number literals.
         //        This hurts readability in this context especially when more complex expressions
         //        are involved and it doesn't add much of value.
         //        Find a way to print constants here without all that jazz.
-        write!(w, "{}", Escape(&default.value(tcx).unwrap_or_else(|| default.expr(tcx))));
+        let repr = konst.value(tcx).unwrap_or_else(|| konst.expr(tcx));
+        if match value {
+            AssocConstValue::TraitDefault(_) => true, // always show
+            AssocConstValue::Impl(_) => repr != "_",  // show if there is a meaningful value to show
+            AssocConstValue::None => unreachable!(),
+        } {
+            write!(w, " = {}", Escape(&repr));
+        }
     }
     write!(w, "{}", print_where_clause(generics, cx, indent, Ending::NoNewline));
 }
@@ -1075,33 +1092,43 @@ fn render_assoc_item(
 ) {
     match &item.kind {
         clean::StrippedItem(..) => {}
-        clean::TyMethodItem(m) => {
+        clean::RequiredMethodItem(m) => {
             assoc_method(w, item, &m.generics, &m.decl, link, parent, cx, render_mode)
         }
         clean::MethodItem(m, _) => {
             assoc_method(w, item, &m.generics, &m.decl, link, parent, cx, render_mode)
         }
-        clean::TyAssocConstItem(generics, ty) => assoc_const(
+        clean::RequiredAssocConstItem(generics, ty) => assoc_const(
             w,
             item,
             generics,
             ty,
-            None,
+            AssocConstValue::None,
             link,
             if parent == ItemType::Trait { 4 } else { 0 },
             cx,
         ),
-        clean::AssocConstItem(ci) => assoc_const(
+        clean::ProvidedAssocConstItem(ci) => assoc_const(
             w,
             item,
             &ci.generics,
             &ci.type_,
-            Some(&ci.kind),
+            AssocConstValue::TraitDefault(&ci.kind),
             link,
             if parent == ItemType::Trait { 4 } else { 0 },
             cx,
         ),
-        clean::TyAssocTypeItem(ref generics, ref bounds) => assoc_type(
+        clean::ImplAssocConstItem(ci) => assoc_const(
+            w,
+            item,
+            &ci.generics,
+            &ci.type_,
+            AssocConstValue::Impl(&ci.kind),
+            link,
+            if parent == ItemType::Trait { 4 } else { 0 },
+            cx,
+        ),
+        clean::RequiredAssocTypeItem(ref generics, ref bounds) => assoc_type(
             w,
             item,
             generics,
@@ -1383,7 +1410,7 @@ fn render_deref_methods(
 fn should_render_item(item: &clean::Item, deref_mut_: bool, tcx: TyCtxt<'_>) -> bool {
     let self_type_opt = match item.kind {
         clean::MethodItem(ref method, _) => method.decl.receiver_type(),
-        clean::TyMethodItem(ref method) => method.decl.receiver_type(),
+        clean::RequiredMethodItem(ref method) => method.decl.receiver_type(),
         _ => None,
     };
 
@@ -1659,7 +1686,7 @@ fn render_impl(
             write!(w, "<details class=\"toggle{method_toggle_class}\" open><summary>");
         }
         match &item.kind {
-            clean::MethodItem(..) | clean::TyMethodItem(_) => {
+            clean::MethodItem(..) | clean::RequiredMethodItem(_) => {
                 // Only render when the method is not static or we allow static methods
                 if render_method_item {
                     let id = cx.derive_id(format!("{item_type}.{name}"));
@@ -1689,7 +1716,7 @@ fn render_impl(
                     w.write_str("</h4></section>");
                 }
             }
-            clean::TyAssocConstItem(ref generics, ref ty) => {
+            clean::RequiredAssocConstItem(ref generics, ref ty) => {
                 let source_id = format!("{item_type}.{name}");
                 let id = cx.derive_id(&source_id);
                 write!(w, "<section id=\"{id}\" class=\"{item_type}{in_trait_class}\">");
@@ -1704,14 +1731,14 @@ fn render_impl(
                     item,
                     generics,
                     ty,
-                    None,
+                    AssocConstValue::None,
                     link.anchor(if trait_.is_some() { &source_id } else { &id }),
                     0,
                     cx,
                 );
                 w.write_str("</h4></section>");
             }
-            clean::AssocConstItem(ci) => {
+            clean::ProvidedAssocConstItem(ci) | clean::ImplAssocConstItem(ci) => {
                 let source_id = format!("{item_type}.{name}");
                 let id = cx.derive_id(&source_id);
                 write!(w, "<section id=\"{id}\" class=\"{item_type}{in_trait_class}\">");
@@ -1726,14 +1753,18 @@ fn render_impl(
                     item,
                     &ci.generics,
                     &ci.type_,
-                    Some(&ci.kind),
+                    match item.kind {
+                        clean::ProvidedAssocConstItem(_) => AssocConstValue::TraitDefault(&ci.kind),
+                        clean::ImplAssocConstItem(_) => AssocConstValue::Impl(&ci.kind),
+                        _ => unreachable!(),
+                    },
                     link.anchor(if trait_.is_some() { &source_id } else { &id }),
                     0,
                     cx,
                 );
                 w.write_str("</h4></section>");
             }
-            clean::TyAssocTypeItem(ref generics, ref bounds) => {
+            clean::RequiredAssocTypeItem(ref generics, ref bounds) => {
                 let source_id = format!("{item_type}.{name}");
                 let id = cx.derive_id(&source_id);
                 write!(w, "<section id=\"{id}\" class=\"{item_type}{in_trait_class}\">");
@@ -1808,11 +1839,13 @@ fn render_impl(
     if !impl_.is_negative_trait_impl() {
         for trait_item in &impl_.items {
             match trait_item.kind {
-                clean::MethodItem(..) | clean::TyMethodItem(_) => methods.push(trait_item),
-                clean::TyAssocTypeItem(..) | clean::AssocTypeItem(..) => {
+                clean::MethodItem(..) | clean::RequiredMethodItem(_) => methods.push(trait_item),
+                clean::RequiredAssocTypeItem(..) | clean::AssocTypeItem(..) => {
                     assoc_types.push(trait_item)
                 }
-                clean::TyAssocConstItem(..) | clean::AssocConstItem(_) => {
+                clean::RequiredAssocConstItem(..)
+                | clean::ProvidedAssocConstItem(_)
+                | clean::ImplAssocConstItem(_) => {
                     // We render it directly since they're supposed to come first.
                     doc_impl_item(
                         &mut default_impl_items,
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 4c8d704e65b..0fb77d38f16 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -469,7 +469,7 @@ fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[cl
 
                 let unsafety_flag = match myitem.kind {
                     clean::FunctionItem(_) | clean::ForeignFunctionItem(..)
-                        if myitem.fn_header(tcx).unwrap().safety == hir::Safety::Unsafe =>
+                        if myitem.fn_header(tcx).unwrap().safety.is_unsafe() =>
                     {
                         "<sup title=\"unsafe function\">⚠</sup>"
                     }
@@ -651,9 +651,11 @@ fn item_function(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, f: &clean::
 fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Trait) {
     let tcx = cx.tcx();
     let bounds = bounds(&t.bounds, false, cx);
-    let required_types = t.items.iter().filter(|m| m.is_ty_associated_type()).collect::<Vec<_>>();
+    let required_types =
+        t.items.iter().filter(|m| m.is_required_associated_type()).collect::<Vec<_>>();
     let provided_types = t.items.iter().filter(|m| m.is_associated_type()).collect::<Vec<_>>();
-    let required_consts = t.items.iter().filter(|m| m.is_ty_associated_const()).collect::<Vec<_>>();
+    let required_consts =
+        t.items.iter().filter(|m| m.is_required_associated_const()).collect::<Vec<_>>();
     let provided_consts = t.items.iter().filter(|m| m.is_associated_const()).collect::<Vec<_>>();
     let required_methods = t.items.iter().filter(|m| m.is_ty_method()).collect::<Vec<_>>();
     let provided_methods = t.items.iter().filter(|m| m.is_method()).collect::<Vec<_>>();
@@ -1926,9 +1928,7 @@ fn item_static(
             buffer,
             "{vis}{safe}static {mutability}{name}: {typ}",
             vis = visibility_print_with_space(it, cx),
-            safe = safety
-                .map(|safe| if safe == hir::Safety::Unsafe { "unsafe " } else { "" })
-                .unwrap_or(""),
+            safe = safety.map(|safe| safe.prefix_str()).unwrap_or(""),
             mutability = s.mutability.print_with_space(),
             name = it.name.unwrap(),
             typ = s.type_.print(cx)
diff --git a/src/librustdoc/html/render/search_index.rs b/src/librustdoc/html/render/search_index.rs
index cfb62c3ca16..fe2e155c9ba 100644
--- a/src/librustdoc/html/render/search_index.rs
+++ b/src/librustdoc/html/render/search_index.rs
@@ -201,7 +201,7 @@ pub(crate) fn build_index(
                             // exported from this same module). It's also likely to Do
                             // What I Mean, since if a re-export changes the name, it might
                             // also be a change in semantic meaning.
-                            .filter(|fqp| fqp.last() == fqp.last());
+                            .filter(|this_fqp| this_fqp.last() == fqp.last());
                         Some(insert_into_map(
                             itemid_to_pathid,
                             ItemId::DefId(defid),
@@ -423,6 +423,14 @@ pub(crate) fn build_index(
                     }
                     Some(path)
                 });
+            } else if let Some(parent_idx) = item.parent_idx {
+                let i = <isize as TryInto<usize>>::try_into(parent_idx).unwrap();
+                item.path = {
+                    let p = &crate_paths[i].1;
+                    join_with_double_colon(&p[..p.len() - 1])
+                };
+                item.exact_path =
+                    crate_paths[i].2.as_ref().map(|xp| join_with_double_colon(&xp[..xp.len() - 1]));
             }
 
             // Omit the parent path if it is same to that of the prior item.
@@ -829,7 +837,7 @@ pub(crate) fn get_function_type_for_search(
         clean::ForeignFunctionItem(ref f, _)
         | clean::FunctionItem(ref f)
         | clean::MethodItem(ref f, _)
-        | clean::TyMethodItem(ref f) => {
+        | clean::RequiredMethodItem(ref f) => {
             get_fn_inputs_and_outputs(f, tcx, impl_or_trait_generics, cache)
         }
         _ => return None,
@@ -1199,10 +1207,11 @@ fn simplify_fn_type<'a, 'tcx>(
                 && let Type::Path { path } = arg
                 && let def_id = path.def_id()
                 && let Some(trait_) = cache.traits.get(&def_id)
-                && trait_.items.iter().any(|at| at.is_ty_associated_type())
+                && trait_.items.iter().any(|at| at.is_required_associated_type())
             {
                 for assoc_ty in &trait_.items {
-                    if let clean::ItemKind::TyAssocTypeItem(_generics, bounds) = &assoc_ty.kind
+                    if let clean::ItemKind::RequiredAssocTypeItem(_generics, bounds) =
+                        &assoc_ty.kind
                         && let Some(name) = assoc_ty.name
                     {
                         let idx = -isize::try_from(rgen.len() + 1).unwrap();
diff --git a/src/librustdoc/html/render/sidebar.rs b/src/librustdoc/html/render/sidebar.rs
index e99e2f04b2c..af39d15f671 100644
--- a/src/librustdoc/html/render/sidebar.rs
+++ b/src/librustdoc/html/render/sidebar.rs
@@ -282,10 +282,10 @@ fn sidebar_trait<'a>(
         res
     }
 
-    let req_assoc = filter_items(&t.items, |m| m.is_ty_associated_type(), "associatedtype");
+    let req_assoc = filter_items(&t.items, |m| m.is_required_associated_type(), "associatedtype");
     let prov_assoc = filter_items(&t.items, |m| m.is_associated_type(), "associatedtype");
     let req_assoc_const =
-        filter_items(&t.items, |m| m.is_ty_associated_const(), "associatedconstant");
+        filter_items(&t.items, |m| m.is_required_associated_const(), "associatedconstant");
     let prov_assoc_const =
         filter_items(&t.items, |m| m.is_associated_const(), "associatedconstant");
     let req_method = filter_items(&t.items, |m| m.is_ty_method(), "tymethod");
diff --git a/src/librustdoc/html/static/js/search.js b/src/librustdoc/html/static/js/search.js
index 9e5cf497211..04eeee37fe8 100644
--- a/src/librustdoc/html/static/js/search.js
+++ b/src/librustdoc/html/static/js/search.js
@@ -2592,7 +2592,12 @@ class DocSearch {
             const writeFn = (fnType, result) => {
                 if (fnType.id < 0) {
                     if (fnParamNames[-1 - fnType.id] === "") {
-                        for (const nested of fnType.generics) {
+                        // Normally, there's no need to shown an unhighlighted
+                        // where clause, but if it's impl Trait, then we do.
+                        const generics = fnType.generics.length > 0 ?
+                            fnType.generics :
+                            obj.type.where_clause[-1 - fnType.id];
+                        for (const nested of generics) {
                             writeFn(nested, result);
                         }
                         return;